Radiolucent, 3-D printed soft tissue retractor

Abstract

A radiolucent, 3-D printed soft tissue retractor includes an elongate, curved support body having a long central axis that exceeds the length of a short, transverse axis. A bone engaging concavity is provided on a first side of the body. A concave soft tissue retracting surface is provided on a second side of the body. An inflection point is provided on the body in between the bone engaging concavity and the soft tissue retracting surface. The soft tissue retractor is configured to cooperate with a second soft tissue retractor and a backing plate to retract tissue and stabilize bones during a surgical distal radius fracture repair.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No. 17/368,623, filed on Jul. 6, 2021, which claims the priority benefit under 35 U.S.C. § 119(e) of U.S. Provisional Application No. 63/050,633, filed Jul. 10, 2020, the entireties of which are hereby incorporated by reference herein.

BACKGROUND OF THE INVENTION

A distal radius fracture is one of the more common hand and wrist surgeries performed. Treatment often requires attachment of a surgical implant to bone structures for adding strength. The surgical procedure for addressing this type of fracture can be complicated due to the number and proximity of adjacent structures, such as muscles, ligaments, tendons, and blood vessels that surround this area. The corresponding procedure requires that the tissues and muscles in the wrist be moved so that the bone can be exposed. Various surgical retraction tools are available to manipulate tissues and anatomical structures during surgery. Conventional retractors include manual articulated or rigid elongation members for positioning the adjacent anatomy by manual operation by a surgeon or assistant.

The standard surgical approach to the distal radius is the volar approach which involves making an incision on the volar aspect (the palm side) of the forearm at the wrist level. This allows for a safe and extensile exposure of the fractured aspect of the distal radius, allowing for reduction of the fracture and placement of hardware to retain the fracture in its correct or reduced position. Most commonly this involves using a plate and screws. The challenge here is that there are numerous structures that run longitudinally down the arm into the hand, and traverse the surgical field. These need to be retracted and protected in order for the procedure to be performed safely and efficiently. There are two types of surgical retractors: handheld devices which require surgeon or assistant to hold in one hand, and self-retaining retractors which do not need to be held in position manually, once they are inserted into the wound.

Notwithstanding the foregoing, there remains a need for an improved retraction system which stabilizes a joint during surgical repair, for any of a variety of joints and bones, including, among others, in the wrist, the Radius, Ulna and carpals and in the ankle, the Tibia and Fibula.

SUMMARY OF THE INVENTION

Systems are disclosed for stabilizing bones or bone fragments during surgical reduction of a fracture and installation of fixation hardware. Although discussed herein primarily in the context of wrist repair, the stabilizing systems of the present invention may be utilized in a variety of other procedures, in which stabilization and tissue retraction may be desirable, including particularly the ankle repair of either the tibia or fibula.

In accordance with one aspect of the present invention, there is provided a stabilizing retractor system for distal radius fracture repair. The system comprises a backing plate configured to support the back of the wrist, the backing plate having a first side accessible on a first side of the wrist, a second side accessible on a second side of the wrist and a longitudinal axis. At least a first soft tissue retractor is also provided, comprising a first support body having a first radius engaging concavity on a first side and on a distal portion of the body and a first soft tissue retracting surface on a second side, and proximal to the first radius engaging concavity.

The stabilizing retractor system may further comprise a second soft tissue retractor, comprising a second support body having a second radius engaging concavity on a first side and a second soft tissue retracting surface on a second side. The system may further comprise a guide on the first soft tissue retractor, configured to direct a wire across the first radius engaging surface. The guide may comprise a lumen, which may extend through the first support body, or may extend through a guide structure carried by the first support body. The lumen may extend along an axis that intersects the surface of the radius in the intended use orientation at an angle that is within about 15 degrees of perpendicular to the surface of the radius, and in some implementations the axis is substantially perpendicular to the surface of the radius.

The system may additionally comprise a connector on a proximal portion of each of the first and second soft tissue retractors, and a tie for attaching the connectors around a back of the wrist and biasing the proximal ends of the first and second soft tissue retractors apart from each other. The tie may be elastic.

The backing plate may have a convex side and a concave side, and may have first and second opposing forceps landing zones on the convex side, configured to facilitate grasping of the retractor system with forceps. The landing zones may comprise an anti slip surface for enhancing attachment of the forceps, which may be a plurality of surface deviations such as a plurality of projections or a plurality of recesses or a plurality of apertures.

There is also provided a soft tissue retractor, having an elongate, curved support body having a proximal end and a distal end and a curved long axis that exceeds the length of a short, transverse axis. A radius engaging concavity may be located on a first side of the body in a distal portion of the body. A concave soft tissue retracting surface may be provided on a second side of the body, and proximal of the radius engaging concavity. An inflection point may occur on the body in between the radius engaging concavity and the soft tissue retracting surface. The inflection point may occur in the distal one half of the body, or in the distal one third or one quarter of the length of the body.

A guide may be provided for guiding a pin over the radius engaging concavity to engage the radius when positioned within the radius engaging concavity. The guide may comprise a lumen. A connector may be provided on the body spaced apart proximally from the radius engaging concavity, for connection to a tie.

Preferably the body is radiolucent, enabling the reduced and stabilized wrist and attached retractor system to be moved as a unit for Xray imaging, and moved back out again without disrupting the orientation of the bones and retractor system.

There is also provided a stabilizing retractor kit. The kit may include a backing plate; a first and second soft tissue retractors; and a tie for connecting the first and second soft tissue retractors. The kit may also include a drill guide.

There is also provided a method of treating a distal radius fracture. The method comprises positioning a backing plate with a wrist contacting front surface and a back surface along the back of a wrist. A distal end of a first soft tissue retractor is engaged with a first side of a radius, and a distal end of a second soft tissue retractor is engaged with a second side of the radius. A proximal end of the first soft tissue retractor and a proximal end of the second soft tissue retractor are moved away from each other to retract opposing sides of an incision; and the first and second soft tissue retractors are connected to retain the incision open. The connecting step may comprise connecting the first and second soft tissue retractors with a tie extending around the back surface of the backing plate. The tie may bias the proximal ends away from each other, and may be elastic. The method may additionally comprise the step of anchoring the first and second soft tissue retractors to the radius.

The method may additionally comprise the step of moving the patient's wrist with the attached stabilizing retractor system into an Xray or other imaging modality field of view, and inspecting the fracture without the stabilizing retractor system blocking any of the image of the fracture and adjacent bones. The wrist may then be moved back out of the imaging field of view for further steps, without having disturbed the fracture. Further steps may include adjustment or installation of fixation hardware, further adjustment of the fracture or removal of the stabilizing retractor system and closure of the surgical site.

There is also provided a method of retracting soft tissue from an incision site to expose a bone. The method may comprise engaging a distal end of a first soft tissue retractor with a first side of the bone, and engaging a distal end of a second soft tissue retractor with a second side of the bone. A proximal end of the first soft tissue retractor and a proximal end of the second soft tissue retractor are moved away from each other to retract opposing sides of an incision; and the first and second soft tissue retractors are connected to retain the incision open. The connecting step may comprise connecting the first and second soft tissue retractors with a tie. The tie may bias the proximal ends of the first and second soft tissue retractors away from each other to retract tissue away from the incision. The tie may be elastic. The method may additionally comprise the step of anchoring the first and second soft tissue retractors to the bone.

The method may further comprise the step of imaging the bone through the retractors with the retractors anchored to the bone, at one or more times during the procedure, enabled by the radiolucent material of the retractors. The method may further comprise the step of reducing two adjacent bone fragments to form a union and placing a plate over the union. The method may additionally comprise the step of clamping the plate against the union and moving the plate, soft tissue retractors and union into an X-ray beam. The clamping step may comprise providing a clamp having a first jaw and a second jaw, placing the first jaw against the plate and placing the second jaw against a convex side of a backing plate attached to the first and second soft tissue retractors. The clamp may then be used to move the retractors, plate and union away from a surgical table, into and out of an X-ray beam and back to the surgical table while maintaining the spatial relationship of the union, plate and retractors without relative movement. In one implementation of the invention, the plate is a volar plate.

In any of the systems and methods disclosed herein, a retractor can be left side or right side specific, or universal to both sides. The retractor may be configured with or without a lumen, and can have a single distal tip or two or more distal tips to facilitate insertion and prying.

A number of the steps in the procedure can be varied in accordance with clinical preference. For example, if the K-wire is placed first, a twisting motion of the left and right retractors opens the incision to facilitate placing the distal tip. If the tip is anchored first and then the retractor is retracted back against soft tissue before placing the K-wire, the surgeon will have better visualization for the K-wire placement in the bone.

In some applications of the method, the bone may be a radius, ulna, or carpals in the wrist or a fibula or a tibia in the ankle.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic representation of a stabilizing retractor system attached to a radius.

FIG. 2 is a perspective view of the system of FIG. 1.

FIG. 3 is an exploded perspective view of a backing plate and two soft tissue retractors.

FIG. 4 is a top perspective view as in FIG. 2, shown being grasped by forceps.

FIG. 5 is a bottom perspective view as in FIG. 2, shown being grasped by forceps.

FIGS. 6A-6G are detail views of a backing plate.

FIGS. 7A-7D are detail views of a soft tissue retractor.

FIGS. 8A-8B are detail views of a drill guide.

FIGS. 9A-9C are additional detail views of a drill guide.

FIGS. 10A-10C are detail views of a soft tissue retractor configured for use on the fibula.

FIGS. 11A-11B are detail views of a soft tissue retractor configured for use on either side of an incision.

FIGS. 12A-12C illustrate a dual headed lunate anchor and drill guide.

FIGS. 13A-13B illustrate a fibula retraction and stabilization system in relation to the ankle.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The stabilizing retractor system of the present invention enables a surgeon to place a joint or limb in a pre-determined position, retract tissue from an incision site, and stabilize the retractors by securing them to an adjacent bone. This eliminates the need for additional clinical personnel to hold the retractors. Although the system described herein can be readily adapted to other surgical procedures throughout the body, it will be detailed herein primarily in the context of wrist or hand surgery as an example. The invention can be readily expanded to multiple other areas with elbow, shoulder, knee, ankle (Tibia and Fibula), and hip surgery being of particular emphasis.

In the context of a wrist surgery, the stabilized retractors also allow the surgeon to manipulate the wrist and location of an implant into a desired orientation, and move the wrist into and out of an X-ray field of view while maintaining the relative orientation of the wrist and of the implant relative to adjacent bone. This enables fine adjustments to the implant based upon the X-ray image since the orientation of the wrist and implant is maintained by the stabilized retractors.

The system may be constructed of radiolucent plastic components that can be fabricated through 3D printing or other more traditional methods like injection molding or thermo-forming. Components may be packaged for a single patient procedure and pre-sterilized. Components may be single use only and disposable.

During the surgical procedure, the clinician will position a primary support shell underneath the limb or joint to be accessed. The clinician will make an incision and then utilize a first and second opposing retractors retract the tissue. The retractors are next fixed with respect to adjacent bone to maintain the retracted tissue. Fixation may be accomplished by pinning each retractor to the radius using at least one K-wire per retractor.

It is likely that each system will thus include 1 support shell and 2 retractors. Each system may be configured with more components based upon customization. The additional components may include, for example, wire or wraps to secure the retractors adequately to the patient, and one or more elastic ties to secure the retractors to the support shell. The components may have attachment anchor guides such as holes and slots as necessary to allow for complementary attachment anchors or attachment to other components.

Customization for use in complicated cases may occur by 3D printing of parts based upon scanned image data on a patient by patient basis. Customization could also be more generic to a particular surgical procedure.

Conventional retractors are metallic and therefore impervious to X-ray imaging. This has impact to the Clinician, the assistant, and the patient. The clinician routinely risks chronic exposure to radiation through repeated exposure of hands during examination of the patient. The assistant has similar risk. Routinely, the assistant and clinician will remove the retractors so that imaging of the reduced bone union and implants can be clearly seen. When the retractors are removed, the clinician or assistant must insert their hands into the x-ray field to try to keep the fracture stable. Maintaining the union stable is not always achieved, potentially requiring additional repositioning and imaging steps. Also, with repeated insertion and removal of the retractors, there is increased risk to nerve and tendons that are repeatedly stretched and manipulated by rigid metallic retractors.

Referring to FIG. 1, there is illustrated a simplified view of the volar aspect of the forearm at the level of the wrist, including a radius 10, an ulna 12, and a scaphoid 14. Numerous additional small bones in the wrist and hand are not discussed herein but are understood in the art.

A stabilizing retractor system 16 in accordance with the present invention is illustrated as mounted to the radius 10. Surrounding soft tissue has been omitted for clarity, however the retractor system 16 will be utilized to separate opposing soft tissue sides of a surgical cut down to expose the radius 10 as is understood in the art.

The system 16 includes a first retractor 18 and a second complementary retractor 20. The second retractor 20 may be a mirror image and/or have similar functionality to the first retractor 18, so primarily only a single retractor will be described in detail.

Retractor 18 comprises a support 22 such as a contoured plate, which will be described in greater detail below. In general, the support 22 includes a radius engaging surface 24 on a first side of the support 22, and a soft tissue retracting surface 26 on a second, opposite side of the support from the radius engaging surface 24. The retractor may be characterized as having a long axis and a transverse short axis

Support 22 additionally comprises a guide 28 defining a lumen 30 for axially movably receiving an attachment pin 29 such as a K wire, for securing the support 22 to the radius 10. The lumen 30 may extend directly through the support 22, or extend through a separate guide structure 32 carried by the support 22. The lumen 30 may be oriented to receive the K wire along a path that is substantially perpendicular to the adjacent surface of the radius 10 in the as mounted orientation. The axis of the guide 28 is generally within about 20 degrees, in many implementations within about 15 degrees or 10 degrees or less of parallel to the long axis. In the illustrated configuration, the guide 28 is substantially parallel to the long axis.

The retractor system may additionally comprise a backing plate 34, for positioning on the opposite side of the wrist from the incision. The backing plate may comprise an elongate arcuate body 36 having an (anatomically as used) proximal end 38, a distal end 40, and an elongate concavity 42 for receiving the wrist.

A convex side of the body 36 may be provided with a forceps landing zone 44, comprising a plurality of recesses 46 for receiving a forceps prong 48 as shown in FIG. 5. At least about 10 or 20 or 50 or more recesses 46 may be provided to produce a large landing zone so that the surgeon will obtain first try engagement of the forceps with the blind side of the backing plate 34 when grasping the stabilized wrist with the forceps such as to move it into a visualization (X-Ray) field and back to the table.

The system 16 may additionally include a drill guide 50 having a proximal handle 52 and a distal guide 54. The guide 54 includes a guide path such as a lumen 56 for receiving a drill or K wire (not illustrated).

Each of the first retractor 18 and second retractor 20 may be provided with a connector 60, 62, respectively. The connector 60, 62 may comprise an aperture, post, snap or other connector for receiving a tie to connect to the backing plate 34. The tie may be elastic, and mounted under tension to place a radially outwardly bias on the connectors 60, 62 to maintain the soft tissue in the retracted orientation. In one implementation of the invention, a single elastic tie may be attached to a first connector, extended around the back of the backing plate, tensioned, and attached to the second connector.

Additional details of a backing plate 34 suited particularly for the wrist are illustrated in FIG. 6A—6G.

Additional details of a soft tissue retractor are illustrated in FIGS. 7A—7D. The first retractor 18 comprises a support body 22 extending between a proximal end 70 and a distal end 72. A connector 76 is provided near the proximal end 70, such as for connection to a tie as has been discussed. The connector 76 may include a post 78 having one end connected to the support 22 and the other end carrying a closed loop or a transverse stop 80 which may reside in an aperture 82 in the support 22. An elastic tie may be looped around the post 78, and restrained from slipping off by the transverse stop. The elastic tie may be looped around the back of the wrist and connected to the corresponding connector on the second retractor, under tension, to pull the first and second retractors away from each other.

The radius engaging surface 24 is provided near the distal end 72, and is separated axially from the soft tissue retention surface 26 by an inflection 84. The soft tissue retention surface 26 may be provided with a greater width than the width of the radius engaging surface 24. In the illustrated implementation, radius engaging service 24 is provided on a projection 86 extending distally beyond the distal end of the guide structure 32, and having a maximum width of no more than about 70%, or no more than about 50% or less of the width of the soft tissue retention surface 26. The width of the projection tapers smaller in a distal direction to a rounded tip 88 which is spaced apart laterally from the longitudinal axis of the lumen 30.

FIGS. 8A-8B show additional details of a lunate retractor which also doubles as a drill guide. The drill guide 50 includes a proximal handle 52 adjacent the proximal end 90 of the drill guide 50. An angled or arcuate body 92 connects the proximal handle 52 and a tubular guide 94 containing a lumen 96 configured to axially removably receive either a drill or a bone anchor such as a K wire. The longitudinal axis of the lumen maybe at least about 45° and preferably between about 80 and 110° from the longitudinal axis of the proximal handle 52. This facilitates grasping the proximal handle 52 and pressing the distal end 54 against the radius when used as a drill guide, or against the lunate, when used for lunate fixation and retraction.

FIGS. 10A through 10C show details of a fibula retractor 98 utilized in an ankle repair procedure on a fibula 150. The fibula retractor 98 is similar to the wrist retractors illustrated previously, except that the distal end 72 of the support 22 is provided with a first distal projection 86 and a distinct second distal projection 100, spaced apart and configured to hook around the bone and resist torsional movement and facilitate increased surface area of the soft tissue contacting surface. Fibula retractors and corresponding backing plate are shown in relation to the ankle in FIGS. 13A-13B, below.

FIGS. 11A-11C illustrate an alternative universal soft tissue retractor 120 which is similar to retractors disclosed previously herein except that the universal retractor 120 can be used on either the right or left side of the incision while previously disclosed retractors were configured for separate left and right side placement. One structural distinction for the universal retractor 120 is the relationship between the K-wire lumen 30 and the tip 122. In use a surgeon may sink the K-wire through the lumen 30 and into the bone, then a twisting moment is created when the previously described retractor is rotated around the K-wire to engage the tip 122. For the universal retractor 120, the intent is to engage the tip 122, then angle back and secure the K-wire. But they are both aligned along a central longitudinal axis of the body 22, so no twisting moment is created.

The proximal portion of the retractor (see, e.g., FIG. 7B) has a longitudinal axis that is at a non normal angle to the longitudinal axis of the K-wire lumen. This is designed to allow the proximal portion of the retractor to reside close to horizontal to the table plane, extending away from the incision and out of the way of the surgeon. This proximal portion acts as a lever which the elastics are always pulling down to keep them out of the way for the surgeon and to keep the retraction of the tissue tight.

FIGS. 12A through 12C illustrate details of a dual headed lunate fixation tool and drill guide 130. The dual headed lunate offers the use of two different profiles. A first profile has a bulbous working end 132 which engages more linear length of the incision compared to the second narrow working end engages less. A first guide lumen 134 is provided at a first end 136 and a second guide lumen 138 is provided at a second end 140 of the drill guide 130. The first and second guide lumen may be substantially parallel to each other and joined by a handle portion 142. The drill guide 130 provides the surgeon with two different bone engaging surfaces and drill guide geometry from which to select in a given procedure.

Procedure steps in an exemplary procedure are described below. Not all steps are necessary in a particular procedure, multiple images may be obtained depending on the nature of the fracture(s), and the order of performance of some of the steps can be varied as will be understood by those of skill in the art.

Take the Backing Plate out of the pouch.

Place Backing Plate on the patient's forearm.

Establish surgical access to the radius.

Take one of the Ulnar side retractors out of the pouch.

Drill the K wire at the desired angle using the handheld radiolucent drill guide.

Slide Ulnar side retractor passing the K-wire through the guide lumen into desired position. Ensure the tip is distal to the guide lumen. Alternatively, insert the ulnar side retractor first, securing the distal tip under the bone. Then insert the K-wire into the lumen and drill into the bone.

Take the Radial side retractor out of the pouch.

Drill the K wire at the desired angle using the handheld radiolucent drill guide.

Slide Radial side retractor passing the K-wire through the guide lumen into desired position. Ensure the tip is distal to the guide lumen.

Secure both Ulnar, Radial, and Backing plate with rubber bands.

If more visualization of the lunate region is needed, use the retractor end of the handheld radiolucent drill guide as a retraction mechanism.

Place implant plate on the space between the two Ulnar fixed parts over the radius

Check where plate was placed relative to the fixed device parts.

Once implant plate is positioned, put some acumen K-wire (2 K wires placed, using the handheld radiolucent drill guide), to hold the plate in position.

Clamp backing plate to the bone.

Place another K wire (Trajectory K wire).

Take imaging shot (Xray with contrast) to judge plate's position with respect to radial bone. Verify bone fragments are correctly positioned to ensure proper range of motion for the patient once healed.

Move the setup until obtaining a proper shot by grabbing onto the clamp.

Drive trajectory k wire forward/backwards or change trajectory as needed.

Reposition the clamp accordingly to get a better view.

Repeat the shot as needed.

Remove K-wires.

Remove rubber bands.

Remove Ulnar and Radial parts.

Remove Backing plate.

Standard surgical closure.

Additional details of a variety of system components are illustrated in the attached Figures, with structural details of specific examples identified in the table below and associated with call out numbers in the drawings. All recited dimensions are related to specific embodiments, but any such recited dimension may be varied by +/−25% or +/−15% or other scaling depending upon the desired application and performance as will be understood by those of skill in the art. Method steps are also described below the feature table, below.

ID	Feature	Description	Specification range
1	Wrist	Base Curvature	Curvature that	Defined by four arc
	Backing		matches the contour	segments with radii
	plate		of the forearm to allow	34, 44, 30, and 40
			for arm resting on the	mm.
			plate.
2		Side Cuts	Two symmetric side	Hourglass shaped
			cuts for matching	Width of the plate at
			forearm shape and	proximal end: 54.52
			ensuring good support	mm.
			and contact.	Width of the plate at
			Cuts are symmetric	distal end: 78.8 mm.
			for device to be used	Width of the plate at
			for both left and right	neck: 57.6 mm.
			arms.	Cut: 40 mm width at
				proximal end
				17.43 mm width at
				distal end
3		Distal wings	Optimized degree of	144° of coverage
			radial/ulnar coverage,	(wing-to-wing) in one
				implementation;
				generally within the
				range of from about
				90 to 180 degrees
4		Length	Optimal length to	160 mm.
			provide good
			structural support of
			forearm.
5		Fillet	Fillet corners to	Radius of 10 mm at
			smooth the edges	distal, 8 mm at
			No sharp surfaces to	proximal end, and 1
			irritate patient skin or	mm throughout.
			represent sharp points
			for gloves.
6		Grid pattern	Covering the distal	Rectangular pattern
			end, to improve the	with 1 mm depth and
			grip and allow for	contoured pockets;
			tunable clamp	grid size may be from
			placement.	about 0.5 to about
				2.0 mm
7		Thickness	Optimal thickness to	At proximal end: 3
			decrease bulkiness	mm
			while ensuring	At distal end: 4 mm;
			stiffness and strength	both generally within
				the range of from
				about 1 mm-4 mm
8		Material	Nylon 12 could	Tensile Modulus:
			ultimately have	1620 MPa
			composite	Tensile Strength: 48
			reinforcement	MPa
				Flexural/Bending
				Modulus (23° C.):
				1,500 MPa
9		Scale	Scaled to 0.8 on x and	Scaling factor: 0.8
			y axes for small size
10	Ulnar	Base Profile	Curved handle	Defined by two 60°
	Plate		extending laterally	arcs with radii 25 mm
	(Left &		away from the incision	and 28.3 mm,
	Right)		site so surgeon's view	respectively. 20 mm
			is un-obstructed.	long rectangular tail
			Length extended	and 0.8 mm thick
			beyond wrist to create	pointy end.
			appropriate vector for
			elastic restraints
11		Tip	Tip created by a cut at	Width: 15.78 mm
			the distal end. For	Height: 11.5 mm
			better attachment of	Fillet of 1.75 mm
			the plate within the	radius.
			bony structures.
			Offset from centerline
			of plate for torsional
			adjustments
			Geometry provides
			leverage
12		Rib	Cylindrical Rib	Rib diameter: 6 mm
			structure appended on	Inner hole diameter:
			opposite side of the	2.2 mm
			tip, with an inner hole	Rib Length: 25 mm
			for K-wire placement	Chamfer: 0.5 mm
			to secure the plates by	distance and 45°
			drilling into the bone.
			Offset from centerline
			to aid in placement
			and rotation
13		Rounded corners at	To improve flexibility,	9 mm radius.
		proximal end	reduce bulkiness and
			smooth the edges.
14		Center cut	To improve flexibility	23.05 mm radius
			when surgeon handles	35 mm cut length
			and fixates the plate at	Fillets of 6 and 8 mm
			different positions.	of radius at edges of
			Narrow neck to reduce	center cut.
			the impact to incision
			length
15		Thickness	Not too thick to avoid	3.3 mm in one
			bulkiness nor too thin	implementation;
			so that it is too fragile	generally within the
				range of from about
				1-4 mm
16		Hook	Located at the	12 mm wide, 8.6 mm
			proximal end. To	long hook over 18.9
			enable elastic band	mm wide, 13.6 mm
			attachment.	long gap.
				Radius of Hook arcs:
				2.5 mm and 1.5 mm
17		Material	Nylon 12 could	Tensile Modulus:
			ultimately have	1620 MPa
			composite	Tensile Strength: 48
			reinforcement	MPa
				Flexural/Bending
				Modulus (23° C.):
				1,500 MPa
18	Lunate	Tip	Curved shape and flat	Two 60° arcs with
	Retractor/		end for optimal tissue	radii 32 mm and 25
	Drill		contact without	mm.
	Guide		impingement risk	Variable thickness:
				from 3.25 to 5.25
				mm.
				Two 7.5- and 10-mm
				radii arcs at the distal
				end of the tip.
19		Cut-out	Cut-outs on sides of	Cut-outs of 10.25-
			tip to confer hourglass	and 15-mm radii
			shape	along length of tip.
				Width at proximal
				end: 16 mm
				Width at distal end:
				14.49 mm
20		Fillet	Fillet corners to	3 of radius
			smooth the edges	surrounding entire
			No sharp surfaces to	part
			irritate patient skin or
			represent sharp points
			for gloves.
21		Loft	Neck of the handle	Rectangular to oval
				shape.
				Loft constraint by two
				40- and 70-mm radii
				arcs.
22		Rib	Rib cylindrical	Rib radius: 3.25 mm
			structure appended on	cylindrical rib of
			same side of the	length 32.5 mm Inner
			retraction end, with an	hole radius: 1.10 mm
			inner hole for K-wire	Chamfer: 0.5 mm
			placement to secure	distance and 45°
			the plates by drilling
			into the bone.
23		Extrusion	Extrusion to increase	Length 52 mm in one
			the length of the	implementation;
			retractor end	generally from about
				40-80 mm
24		Handle	Hole left that acts as	25-mm long, 6.5-mm
			handle for improved	wide cut with the
			grip and potential	shape of a slot in one
			interface with elastic	implementation;
			restraints	length generally from
				about 20-50 mm
25		Fillet	Fillets along the rib for	0.5-mm fillets at
			smoothing purposes.	chamfer
			No sharp surfaces to	1 mm fillet along
			irritate patient skin or	length of the rib
			represent sharp points
			for gloves.
26		Fillet	Fillets at the distal end	Radius 1 mm along
			and handle for	tip width.
			smoothing purposes.	Radius 2 mm along
			No sharp surfaces to	handle
			irritate patient skin or
			represent sharp points
			for gloves.
27		Duality	Dual device useful for
			both tissue retraction
			and as a drill guide for
			K-wire insertion
28	Ankle	Base Curvature	Curvature that	Defined by four arc
	Backing		matches the contour	segments with radii
	Plate		of the _ to allow for _	50, 54, 37.5, and
			resting on the plate.	41.5 mm.
29		Side Cuts	Two symmetric side	Hourglass shaped
			cuts for matching _	Width of the plate at
			shape and ensuring	proximal end: 54.05
			good support and	mm.
			contact.	Width of the plate at
			Cuts are symmetric	distal end: 78.89 mm.
			for device to be used	Width of the plate at
			for both left and right	neck: 50 mm.
			legs.	Cut: 40 mm width at
				proximal end
				17.3 mm width at
				distal end
30		Distal wings	Optimized degree of	144° of coverage
			tibial coverage.	(wing-to-wing)
31		Length	Optimal length to	160 mm.
			provide good
			structural support of _.
32		Fillet	Fillet corners to	Radius of 10 mm at
			smooth the edges	distal, 8 mm at
			No sharp surfaces to	proximal end, and 1
			irritate patient skin or	mm throughout.
			represent sharp points
			for gloves.
33		Grid pattern	Covering the _end, to	Rectangular pattern
			improve the grip and	with 1 mm depth and
			allow for tunable	contoured pockets
			clamp placement.
34		Thickness	Optimal thickness to	At proximal end: 3
			decrease bulkiness	mm
			while ensuring	At distal end: 4 mm
			stiffness and strength
35		Material	Nylon 12 could	Tensile Modulus:
			ultimately have	1620 MPa
			composite	Tensile Strength: 48
			reinforcement	MPa
				Flexural/Bending
				Modulus (23° C.):
				1,500 MPa
36	Ankle	Base Profile	Curved handle	Defined by two 60°
	side		extending laterally	arcs with radii 25 mm
	retractor		away from the incision	and 28.3 mm,
			site so surgeon's view	respectively. 20 mm
			is un-obstructed.	long rectangular tail
			Length extended	and 0.8 mm thick
			beyond ankle to create	pointy end.
			appropriate vector for
			elastic restraints
37		Tips	Two tips created,	Width: 15.78 mm
			mirror images of each	Height: 11.5 mm
			other, by a cut at the	Fillet of 1.75 mm
			distal end. For better	radius.
			attachment of the
			plate within the bony
			structures.
			Geometry provides
			leverage
38		Rounded corners at	To improve flexibility,	9 mm radius.
		proximal end	reduce bulkiness and
			smooth the edges.
39		Side Relieves	Two center cuts on	22.5 mm radius
			each side.	35 mm cut length
			To improve flexibility	Fillets of 5 mm of
			when surgeon handles	radius at edges of
			and fixates the plate at	center cut
			different positions.
			Narrow neck to reduce
			the impact to incision
			length
40		Thickness	Not too thick to avoid	3.3 mm
			bulkiness nor too thin
			so that it is too fragile
41		Hook	Located at the	Tilted 25.5° outward.
			proximal end. To	16 mm wide, 15.2
			enable elastic band	mm long hook over
			attachment.	22 mm wide, 20 mm
			Slightly bend outwards	long gap.
			to aid in rubber band	Radius of Hook arcs:
			placement.	4 mm and 1 mm
42		Material	Nylon 12 could	Tensile Modulus:
			ultimately have	1620 MPa
			composite	Tensile Strength: 48
			reinforcement	MPa
				Flexural/Bending
				Modulus (23° C.):
				1,500 MPa
43	System	Tightening mechanism	Grid pattern improving
			grip for clamping at
			different locations.
44		Compatibility	k-wires and clamps
45		Adjustability after anchoring	Variable tensioning
			with elastic bands to
			easily adjust positions
46	Clinical	Position verification	Device made of Nylon
			which is radiolucent,
			position can be
			verified during
			fluoroscopy imaging.
47		Variants of location	Different scales for
			different patient sizes.
48		Radiolucency	Materials transparent
			to X-rays
49		Hands free	Self-retaining
			mechanism via elastic
			bands and clamp
			placement
50		Permanent thru procedure	Self-retaining
			mechanism via elastic
			bands and clamp
			placement

Claims

1. A soft tissue retractor, comprising:

an elongate, curved support body having a length that exceeds a width;

a bone engaging concavity on a first side of the body;

a concave soft tissue retracting surface on a second side of the body;

an inflection point on the body in between the bone engaging concavity and the soft tissue retracting surface; and

a lumen;

wherein a width of the bone engaging concavity is less than a width of the soft tissue retracting surface;

wherein the width of the bone engaging concavity tapers to a taper point in a direction away from the soft tissue retracting surface, wherein the taper point is spaced apart laterally from the lumen.

2. A soft tissue retractor as in claim 1, further comprising a guide for guiding a pin over the bone engaging concavity.

3. A soft tissue retractor as in claim 2, wherein the guide comprises the lumen.

4. A soft tissue retractor as in claim 3 wherein the lumen extends through the support body.

5. A soft tissue retractor as in claim 3, wherein the lumen is substantially linear.

6. A soft tissue retractor as in claim 3, wherein the lumen is configured to direct a wire into a radius when the bone engaging concavity is engaged with the radius.

7. A soft tissue retractor as in claim 4, wherein the lumen is configured to be perpendicular to a surface of the radius when the bone engaging concavity is engaged with the radius.

8. A soft tissue retractor as in claim 1, further comprising a connector on the body spaced apart from the bone engaging concavity, for connection to a tie.

9. A soft tissue retractor as in claim 1, wherein the body is radiolucent.

10. A soft tissue retractor as in claim 1, wherein the body is 3-D printed.

11. A soft tissue retractor as in claim 1, wherein the width of the bone engaging concavity is no more than about 70% of the width of the soft tissue retracting surface.

12. A soft tissue retractor as in claim 8, wherein the connector comprises an aperture.

13. A soft tissue retractor as in claim 12, further comprising a post in the aperture.

14. A soft tissue retractor, comprising:

an elongate, curved support body having a length that exceeds a width;

a bone engaging concavity on a first side of the body;

a concave soft tissue retracting surface on a second side of the body,

an inflection point on the body in between the bone engaging concavity and the soft tissue retracting surface; and

a guide;

wherein a width of the bone engaging concavity is less than a width of the soft tissue retracting surface;

wherein the width of the bone engaging concavity tapers to a taper point in a direction away from the soft tissue retracting surface, wherein the taper point is spaced apart laterally from the guide.

15. A soft tissue retractor as in claim 14, wherein the taper point is laterally offset from a center of the body.

16. A soft tissue retractor as in claim 14, wherein the guide is configured to guide a pin over the bone engaging concavity.

17. A soft tissue retractor as in claim 14, further comprising a connector on the body spaced apart from the bone engaging concavity, for connection to a tie.

18. A soft tissue retractor as in claim 14, wherein the body is radiolucent.

19. A soft tissue retractor as in claim 14, wherein the body is 3-D printed.

20. A soft tissue retractor as in claim 14, wherein the width of the bone engaging concavity is no more than about 70% of the width of the soft tissue retracting surface.